In vitro eye irritation testing models may play pivotal role in effort to pursue mild baby cleansers.

In recent years, mild baby cleansers have experienced ever-growing demand from caregivers. In the meantime, formulation developers are in practical need for a method(s) to screen mild formulations. In the present study, we aim to repurpose the HET-CAM and SkinEthic™ models to further classify in vivo nonirritant baby cleansing formulations into mild and less mild categories. Both methods were modified to best describe the samples' irritation potential. The results showed that both models successfully classified the formulations into mild and less mild categories according to our customized criteria. For the HET-CAM, the medians of mean irritation scores (IS) were 3.0 for mild formulations (with 0 ≤ mean IS ≤4.5), and 5.0 for less mild formulations (with mean IS values all equaled 5), respectively. And for the SkinEthic™ model, the median relative viabilities were 69.46% for less mild formulations (with 46.80% ≤ mean relative viability ≤84.76%), and 99.96% for mild formulations (with 90.57% ≤ mean relative viability ≤124.58%). Thirty out of 35 formulations were predicted consistently between the HET-CAM and SkinEthic™ model. Statistical analysis of the agreement between predictions made by the two models demonstrated substantial agreement with a Cohen's kappa coefficient of 0.713 (P < 0.001). We conclude that the HET-CAM and SkinEthic™ models are promising in vitro alternatives for screening mild formulations.

Investigation of actual exposure to facial sheet mask preceding its risk assessment.

The present study aimed to reveal the amount per application of facial sheet masks and its influencing factors in Chinese population to form the base for an accurate exposure assessment. A total of 175 healthy subjects aged 18 years or older were recruited and divided into two subgroups: one group of 35 subjects were asked to apply same mask for 5, 10, 15, 20, 25, and 30 min respectively, and the other 140 subjects were instructed to apply one of four types of facial sheet masks presented in the market for 15 min. Furthermore, phenoxyethanol and methylparaben were measured to reflect actual exposure to chemicals. The sharp increase in the relative exposure to phenoxyethanol (CAS NO.122-99-6) and methylparaben at 25 min and longer suggests applying facial sheet masks for longer than 20 min may drive the exposure to hazardous chemicals to increase significantly. The 90th percentile of amount per application for plant-cellulose, bamboo charcoal fiber, bio-cellulose, and binchotan charcoal fiber-based masks was 5.753, 5.371, 5.017, and 4.821 g respectively. In addition, men and subjects with sebaceous skin demonstrated lower amount per application compared to women and subjects with dry skin, respectively. Finally, our data showed that the larger the contacting area between face and mask, the more amount per application. We concluded that the appropriate time of application should be less than 20 min. And mask fabrics, gender, sebum content, and contacting area could significantly impact the risk assessment of facial sheet masks. Our data for the first time provides insights into a realistic risk assessment of facial sheet masks in Chinese population.

Urinary metabolomics reveals novel interactions between metal exposure and amino acid metabolic stress during pregnancy.

Pregnant women are a unique group undergoing profound structural modifications in uterus, breast, adipose tissue and extracellular fluids. Amino acid metabolic stress is a unique physical process that occurs during pregnancy. Metals constitute a fundamental part of the maternal body and have a universal effect on amino acid metabolism. However, the exact interaction between metals and amino acid metabolism during pregnancy is unknown. The aim of the present study was to determine the correlations of metals with amino acid metabolic intermediates in the urine of 232 healthy pregnant women in their first, second and third trimesters during normal pregnancy. Sixteen metals in the urine of 232 healthy pregnant women in their first, second and third trimesters were quantified using inductively coupled plasma mass spectrometry (ICP-MS). An ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometer (UPLC-QTOFMS)-based metabolomics approach was conducted to detect intermediate products involved in amino acid metabolism during the entire pregnancy period. A panel regression model was established to investigate the relationship between urine metals and amino acid metabolism. Seven metals-cadmium, cobalt, copper, cesium, manganese, thallium and vanadium-showed significant association with amino acid metabolic intermediates, including 2-oxoarginine, 3-indoleacetonitrile, indole, indole-5,6-quinone, N2-succinyl-l-glutamic acid 5-semialdehyde, N-methyltryptamine and N-succinyl-l,l-2,6-diaminopimelate, in the healthy pregnant women. These findings indicated that exposure to cadmium, cobalt, copper, cesium, manganese, thallium and vanadium significantly affected the metabolic status of tryptophan, arginine, proline, tyrosine and lysine metabolism in the maternal body during normal pregnancy.

Prenatal exposure to bisphenol A and risk of allergic diseases in early life.

BACKGROUND: Prenatal exposure to bisphenol A (BPA) affects immune system and promotes allergy and asthma in mice, but findings in human studies are limited. We investigated whether prenatal exposure to BPA is associated with increased risk of allergic diseases in infants. METHODS: We measured BPA concentrations in maternal urine samples collected at delivery from 412 women in Wuhan, China. The occurrence of allergic diseases including eczema and wheeze were assessed at age 6 mo through questionnaires. We used logistic regression to evaluate the association between urinary BPA levels and the risk of allergic diseases. RESULTS: Mothers of infants with allergic diseases had significantly higher urinary BPA levels than those of infants without allergic diseases (median: 2.35 vs. 4.55 µg/l, P = 0.03). Increased risk of infant allergic diseases was associated with creatinine-adjusted maternal urinary BPA concentrations. And this association was limited to females (odds ratio (OR) = 1.36; 95% confidence interval (CI): 1.10-1.79) rather than males. After stratification by maternal age, the association was only significant in infants of mothers who were younger than 25 y old (OR = 1.90; 95% CI: 1.09-3.29). CONCLUSION: Prenatal exposure to BPA may potentially increase the risk of allergic diseases at very early life in female infants.

Pancreatic impairment and Igf2 hypermethylation induced by developmental exposure to bisphenol A can be counteracted by maternal folate supplementation.

Increasing evidence indicates that bisphenol A (BPA), a widely manufactured environmental pollutant, can induce changes in DNA methylation paatterns, which is a potential mechanism linking this environmental exposure to disease development. We investigated the influence of developmental exposure to BPA on pancreatic DNA methylation patterns and whether maternal folate supplementation can modify the epigenetic status and pancreatic impairment induced by BPA. Our results showed that maternal dietary folate supplementation in rats exposed to BPA counteracted the observed BPA-induced pancreatic impairments in the offspring, which included disrupted insulin secretion and glucose intolerance, and impaired morphology and ultrastructure of ß cells. Moreover, these pancreatic dysfunctions were shown to be associated with low expression and DNA hypermethylation of insulin-like growth factor-2 (Igf2) in islets induced by exposure to BPA during the developmental period. Importantly, maternal dietary folate supplementation was demonstrated to negate this Igf2 DNA hypermethylation in the offspring, which was consistent with the upregulation of Igf2 expression. Overall, our results suggest that early developmental exposure to BPA alters the DNA methylation of Igf2, that these altered methylation patterns are associated with impaired ß-cell function in the offspring and that these effects can be counteracted by maternal folate supplementation. Copyright © 2017 John Wiley & Sons, Ltd.

Maternal urinary cadmium concentrations in relation to preterm birth in the Healthy Baby Cohort Study in China.

BACKGROUND: Prenatal cadmium (Cd) exposure has been associated with adverse birth outcomes, but the findings of previous studies are inconsistent. The aim of this study was to evaluate the association between prenatal Cd exposure and birth outcomes. METHODS: This study was conducted in 5364 pregnant women with a live singleton birth, who were recruited between September 2012 and October 2014 in the Healthy Baby Cohort (HBC) in Wuhan, China. Gestational age (in days) was estimated using both the woman's last menstrual period (LMP) and ultrasound data. All the birth outcomes including birth weight and birth length were measured in the hospital within one hour after birth through standardized procedures. Cd was measured in maternal urine collected before delivery with inductively coupled plasma mass spectrometry. RESULTS: The geometric mean of Cd concentration in maternal urine was 0.55 (range 0.01-2.85) µg/g creatinine. We found each ln-unit increase in Cd concentration (µg/g creatinine) in maternal urine was associated with decreased gestational age [adjusted ß=-0.77day; 95% confidence interval (CI): -1.15, -0.39 for all infants; -0.77; 95% CI: -1.29, -0.25 for boys; and -0.80; 95% CI: -1.35, -0.25 for girls]. Increased likelihood of preterm birth (PTB) was associated with ln-unit increase in urinary Cd (µg/g creatinine) [adjusted odds ratio (OR)=1.78; 95% CI: 1.45, 2.19 for all infants; 1.97; 95% CI: 1.46, 2.65 for boys; and 1.67; 95% CI: 1.24, 2.25 for girls]. Maternal urinary Cd was not significantly associated with low birth weight (LBW) and small for gestational age (SGA). CONCLUSIONS: Maternal exposure to Cd during pregnancy was associated with decreased gestational age and increased likelihood of PTB.

Free and total urinary phthalate metabolite concentrations among pregnant women from the Healthy Baby Cohort (HBC), China.

Total urinary phthalate metabolites (the free plus glucuronidated forms) have been frequently measured in the general population. However, data are limited on the free forms which may be more bioactive, especially for sensitive population such as pregnant women. Here the data gap was addressed by measuring concentrations of free and total forms of six phthalate metabolites in 293 urine samples from pregnant women at delivery, who were randomly selected from the prospective Healthy Baby Cohort (HBC), China. We observed detectable concentrations of the total amount of phthalate metabolites in all urine samples. The geometric mean (GM) urinary concentrations of free and total mono-butyl phthalate (MBP) (5.20, 54.49ng/mL) were the highest, followed by mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) (4.52, 7.27ng/mL). For most of phthalate metabolites, urinary concentrations were significantly higher in women who were nulliparous. Significantly higher concentrations of mono-ethyl phthalate (MEP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) were found in women who had higher educational level. To our knowledge, this is the first study to report the free and total forms of phthalate metabolites among pregnant women in China. The results suggest that exposure characteristics may be related to parity and education.

Perinatal exposure to low-dose bisphenol A disrupts learning/memory and DNA methylation of estrogen receptor alpha in the hippocampus.

Developmental exposure to bisphenol A (BPA) has been indicated to pose long-lasting effects on brain development and behaviors in adulthood. Previous studies have also shown that BPA may disrupt the epigenetic programming of genes in the brain. Here, we focused on investigating the effects of perinatal exposure to low-dose BPA on learning/memory function and emotional regulation, as well as the associated molecular events. Pregnant Sprague-Dawley (SD) rats were treated with control corn oil or BPA (40 µg kg-1 per day) throughout gestation and lactation. Morris water maze (MWM) and elevated plus maze (EPM) were used to evaluate learning/memory and anxiety-like behaviors at postnatal day (PND) 60 and 85 respectively. The expression level of mRNA for estrogen receptors (ER), ERα and ERß, in the hippocampus and the serum corticosterone level were determined, as well as the DNA methylation status of the ERα gene promoter. Perinatal exposure to BPA prolonged the escape latency independent of gender, and decreased the percentage of time spent in the target quadrant when examined in the MWM task. While no substantial alteration was observed in the EPM test, the serum corticosterone level was altered in a gender-specific manner. BPA also decreased the expression of mRNA for ERα in the hippocampus, along with elevated DNA methylation of the ERα gene promoter. These results suggest that perinatal exposure to BPA impairs learning/memory function and elevated DNA methylation of the ERα gene in the hippocampus may be involved.

Epigenetic disruption and glucose homeostasis changes following low-dose maternal bisphenol A exposure.

Developmental exposure to bisphenol A (BPA) has been linked to impaired glucose homeostasis and pancreatic function in adulthood, which has been hypothesized to result from the disruption of pancreatic ß-cell development at early life. Here we evaluated whether maternal BPA exposure disrupts ß-cell development and glucose tolerance and the role of epigenetic modifications of key regulator in this process. We found that maternal exposure to BPA (10 µg kg-1 d-1) reduced the pancreatic ß-cell mass and the expression of pancreatic and duodenal homeobox 1 (Pdx1) at birth, as well as the expression of Pdx1 at gestational day (GD) 15.5. In parallel with the decreased expression of Pdx1, histones H3 and H4 deacetylation, along with demethylation of histone 3 lysine 4 (H3K4) and methylation of histone 3 lysine 9 (H3K9), were found at the promoter of Pdx1, while no significant changes in DNA methylation status were detected at this region. Moreover, these alterations were observed in adult life along with impaired glucose tolerance. We conclude that maternal exposure to BPA reduces pancreatic ß-cell mass at birth by reducing PDX1+ progenitors during fetal development through altering the histone modifications of Pdx1, which can be propagated to later life and increase the susceptibility to glucose intolerance.

Maternal urinary bisphenol A levels and infant low birth weight: A nested case-control study of the Health Baby Cohort in China.

BACKGROUND: Exposure to bisphenol A (BPA), a known endocrine disruptor, has been demonstrated to affect fetal development in animal studies, but findings in human studies have been inconsistent. OBJECTIVES: We investigated whether maternal exposure to BPA during pregnancy is associated with an increased risk of infant low birth weight (LBW). METHODS: A total 452 mother-infant pairs (113 LBW cases and 339 matched controls) were selected from the participants enrolled in the prospective Health Baby Cohort (HBC) in Wuhan city, China, during 2012-2014. BPA concentrations were measured in maternal urine samples collected at delivery, and the information of birth outcomes was retrieved from the medical records. A conditional logistic regression was used to evaluate the relationship between urinary BPA levels and LBW. RESULTS: Mothers with LBW infants had significantly higher urinary BPA levels (median: 4.70µg/L) than the control mothers (median: 2.25µg/L) (p<0.05). Increased risk of LBW was associated with higher maternal urinary levels of BPA [adjusted odds ratio (OR)=3.13 for the medium tertile, 95% confidence interval (CI): 1.21, 8.08; adjusted OR=2.49 for the highest tertile, 95% CI: 0.98, 6.36]. The association was more pronounced among female infants than among male infants, with a statistical evidence of heterogeneity in risk (p=0.03). CONCLUSIONS: Prenatal exposure to higher levels of BPA may potentially increase the risk of delivering LBW infants, especially for female infants. This is the first case-control study to examine the association in China.

Paternal BPA exposure in early life alters Igf2 epigenetic status in sperm and induces pancreatic impairment in rat offspring.

Exposure to endocrine disruptors in utero appears to alter epigenetics in the male germ-line and subsequently promote adult-onset disease in subsequent generations. Fetal exposure to bisphenol A (BPA), a highly prevalent endocrine disruptor in environment, has been shown to alter epigenetic modification and result in glucose intolerance in adulthood. However, whether fetal exposure to BPA can induce epigenetic modification and phenotypic changes in their subsequent offspring are still unclear. The present study was designed to investigate whether exposure to BPA in early life induced glucose intolerance in the offspring through male germ line, and the underlying epigenetic molecular basis. F0 pregnant SD rats were received corn oil or 40 µg/kg/day of BPA during gestation and lactation. F1 male rats were maintained to generate F2 offspring by mating with untreated female rats. Both the F1 rats after weaning and the F2 offspring were not received any other treatments. Our results showed that male F2 offspring in the BPA group exhibited glucose intolerance and ß-cell dysfunction. Decreased expression of Igf2 and associated hypermethylation of Igf2 were observed in islets of male F2 offspring. In addition, similar effects were observed in female F2 animals, but the effects were more pronounced in males. Moreover, abnormal expression and methylation of Igf2 was observed in sperm of adult F1 male rats, indicating that epigenetic modification in germ cells can be partly progressed to the next generation. Overall, our study suggests that BPA exposure during early life can result in generational transmission of glucose intolerance and ß-cell dysfunction in the offspring through male germ line, which is associated with hypermethylation of Igf2 in islets. The changes of epigenetics in germ cells may contribute to this generational transmission.

BPA-induced DNA hypermethylation of the master mitochondrial gene PGC-1α contributes to cardiomyopathy in male rats.

Implication of environmental endocrine disruptors, such as bisphenol A (BPA), on the development of cardiopathy has been poorly investigated. The aim of the study was to investigate the effects of long-term exposure to BPA at the reference dose on the myocardium of rats, and the underlying mechanisms. Male rats received corn oil or 50 µg/kg/day of BPA since delactation. At 24 and 48 weeks (wk), cardiac function and mitochondrial function were examined. The mRNA expression and the methylation status of PCG-1α, a major regulator of mitochondrial biogenesis in cardiac muscle, were also tested. At 48 wk, BPA-exposed rats displayed cardiomyopathy, characterized by myocardium hypertrophy, cardiomyocyte enlargement, and impairment of cardiac function. At 24 wk, significantly reduced ATP production, dissipated mitochondrial membrane potential (Ψm) and declined mitochondrial respiratory complex (MRC) activity in cardiomyocytes were observed in BPA-exposed rats compared with the control rats, indicating a decrease in mitochondrial function occurs before the development of cardiomyopathy. Additionally, BPA exposure decreased the expression of PGC-1α and induced hypermethylation of PGC-1 α in heart tissue in 24- and 48-week-old rats. The change in methylation of PGC-1α was observed more pronounced in BPA-exposed rats at 48 wk. Overall, long-term BPA exposure induces cardiomyopathy in male rats, and the underlying mechanism may involve the impairment of cardiac mitochondrial function and the disturbance of methylation of PGC-1α.

F0 maternal BPA exposure induced glucose intolerance of F2 generation through DNA methylation change in Gck.

BPA, a common environmental endocrine disruptor, has been reported to induce epigenetic changes and disrupt glucose homeostasis in F1 offspring through maternal exposure. However, no studies have examined whether maternal BPA exposure can exert multigenerational effects of glucose metabolic disorder on F2 generation through the altered epigenetic information. The aim of the current study was to investigate whether BPA exposure can disrupt glucose homeostasis in F2 offspring and the underlying epigenetic mechanism. In the present study, F0 pregnant dams were orally administered at a daily dose of 40µg/kg body weight during gestation and lactation. The F1 and F2 generations were obtained and not exposed to BPA anymore. The glucose and insulin tolerance tests were carried out to evaluate the glucose homeostasis level. The relative hormone level and the relative gene expression were also examined. F2 generation was found to exhibited glucose intolerance and insulin resistance in ipGTT and ipITT, as well as the downregulation of glucokinase (Gck) gene in liver. DNA methylation pattern of Gck promoter in the F2 generation of hepatic tissue and F1 generation of sperm was then performed. The Gck promoter in F2 hepatic tissue became completely methylated in the all CpG sites compared with five unmethylated sites in controls. In the F1 sperm, the global DNA methylation was decreased. However, there is only CpG site -314 was differently methylated between BPA and controls in sperm. In conclusion, F0 maternal BPA exposure during gestation and lactation can induce impaired glucose homeostasis in the F2 offspring through the transmission of sperm. The underlying epigenetic modifications in the sperm of F1 generation remain to be further elucidated.

Mitochondrial dysfunction in early life resulted from perinatal bisphenol A exposure contributes to hepatic steatosis in rat offspring.

An emerging literature suggests that bisphenol A (BPA), a widespread endocrine disrupting chemical, when exposure occurs in early life, may increase the risk of metabolic syndrome. In this study, we investigated the hypothesis that perinatal exposure to BPA predisposed offspring to fatty liver disease: the hepatic manifestation of metabolic syndrome, and its possible mechanism. Pregnant Wistar rats were administered with BPA (40µg/kg/day) or vehicle during gestation and lactation. Liver histology, biochemical analysis, transcriptome, and mitochondrial function were examined in male offspring at postnatal 3, 15 and 26 weeks. At 3 weeks of age, abnormal liver morphology and function were not observed in the BPA-exposed offspring, but a decrease in mitochondrial respiratory complex (MRC) activity (I and III) and significant changes in gene expression involved in mitochondrial fatty acid metabolism were observed compared with controls. At 15 weeks, micro-vesicular steatosis in liver, up-regulated genes involved in lipogenesis pathways, increased ROS generation and Cytc release were observed in the BPA-exposed offspring. Then, extensive fatty accumulation in liver and elevated serum ALT were observed in BPA-exposed offspring at 26 weeks. In the longitudinal observation, hepatic mitochondrial function including MRC activity, ATP production, ROS generation and mitochondrial membrane potential were progressively worsened in the BPA-exposed offspring. Perinatal BPA exposure contributes to the development of hepatic steatosis in the offspring of rats, which may be mediated through impaired hepatic mitochondrial function and up-regulated hepatic lipid metabolism.

Early-life exposure to bisphenol a induces liver injury in rats involvement of mitochondria-mediated apoptosis.

Exposure to bisphenol A (BPA), a monomer widely used to manufacture polycarbonate plastics, has been reported to be associated with abnormalities of liver function and hepatic damage. However, the molecular mechanism under the pathogenesis of hepatic injury is unclear. In this study, the effect of perinatal exposure to BPA at the reference dose of 50 µg/kg/day on the apoptotic index in the liver of rat offspring was investigated. Increased levels of ALT and enhanced cell apoptosis were observed in the liver of rat offspring at 15 and 21 weeks, and significantly increased activity of caspase-3 and caspase-9 and elevated levels of cytochrome c were also confirmed. In addition, significant change in the expression levels of Bcl-2 and Bax were found in BPA-treated offspring at 21 weeks. For in vitro experiments, liver mitochondria were isolated from neonatal rats and were treated with BPA. BPA treatment led to a significant increase in mitochondrial permeability transition. Moreover, the supernatant from BPA-treated mitochondria significantly increased apoptotic changes in nuclei isolated from liver tissue. In conclusion, the study demonstrates that BPA induces mitochondria-mediated apoptosis in hepatic cells, which may contribute to long-term hepatotoxicity induced by early-life exposure to BPA.

Prenatal exposure to bisphenol A at the reference dose impairs mitochondria in the heart of neonatal rats.

Bisphenol A (BPA) exposure has been reported to be epidemiologically associated with heart disease. As mitochondria play an important role in the early development of the heart and in the pathogenesis of heart disease, the current study investigated the possibility of cardiac mitochondrial injury in neonatal rat heart prenatally exposed to BPA. Pregnant Wistar rats were exposed to BPA 50 µg kg(-1) day(-1) or corn oil 1 ml kg(-1) by oral gavage throughout gestation. Heart samples from pups on postnatal day 1 were isolated for analysis. Ultrastructure results showed mild swelling with dissociation of cristae in myocardial mitochondria of BPA-treated rats. Additionally, mitochondrial membrane potential and the activity of respiratory chain complex II were significantly decreased. However, the activities of other three complexes (CI, CIII, CIV) and cardiac histology stayed normal. The expression levels of some key regulators involved in mitochondria energy metabolism and ATP-generating pathways were downregulated. The study demonstrated for the first time that prenatal exposure to BPA at the reference dose could impair mitochondria in the hearts of neonatal rats.